[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050535
TWDAT

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

Major Hurricane Larry is centered near 18.0N 48.0W at 05/0300
UTC or 790 nm E of the Leeward Islands moving WNW at 12 kt.
Estimated minimum central pressure is 958 mb. Maximum sustained
wind speed is 105 kt with gusts to 130 kt. The eye diameter is
45 nm on IR satellite imagery. Numerous moderate to strong
convection is noted within 180 nm of the center in the N
semicircle, 150 nm SE quadrant and 90 nm SW quadrant. Seas are
up to 41 ft with 12 ft seas extending within 300 nm in the N
semicircle and 240 nm in the S semicircle. A turn toward the
northwest is expected this morning, with Larry maintaining that
heading at a gradually slower forward speed through Tuesday.
Little change in strength is forecast during the next few days,
although fluctuations in intensity are possible. Larry is
expected to remain a major hurricane through the middle of the
upcoming week. Swell generated by Larry are expected to reach
the Lesser Antilles today, and will spread westward to portions
of the Greater Antilles, the Bahamas, and Bermuda Monday and
Tuesday. Significant swells will likely reach the east coast of
the United States and Atlantic Canada around midweek. Please
read the latest High Seas Forecast issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An east Atlantic tropical wave has an axis along 17/18W from
03N-20N, moving W at 10 kt. Scattered moderate convection is
noted from 09N-14N between 14W-19W.

An Atlantic Ocean tropical wave has an axis along 35W from
05N-19N, moving W at 10 kt. The wave is situated at the leading
edge of a Saharan dust plume. As a result of the dry Saharan
air, no significant convection is noted with the wave at this
time.

A central Caribbean Sea tropical wave has an axis along 74W from
western Haiti to central Colombia, moving W at 15 kt. Scattered
moderate and isolated strong convection is seen near the wave
axis over Haiti and Colombia, with only isolated showers over
the Caribbean waters. ASCAT shows fresh E trades east of the
wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of southern Mauritania
near 17N16W to 06N27W. The ITCZ is from 06N27W to 05N34W, then
continues W of a tropical wave from 05N37W to the coast of
Venezuela near 10N61W. Aside from the convection mentioned
above, isolated moderate thunderstorms are noted within 150 nm
either side of the ITCZ between 37W-46W.

GULF OF MEXICO...

A stationary front extends from Clearwater, Florida to 28.5N
85W, then continues as a warm front to near Slidell, Louisiana.
An isolated shower is possible near the front. A 1015 mb surface
high pressure is analyzed near 27.5N 92.5W. A surface trough
near the west coast of the Yucatan Peninsula and another trough
farther west near Veracruz are inducing scattered moderate and
isolated strong convection south of 20.5N, including inland over
Mexico. Numerous strong convection is currently over Guatemala
and southern Belize. A recent ASCAT pass shows light to gentle
winds across most of the basin, with moderate E winds in the
southwest Gulf. Seas are 1 to 3 ft across the basin.

For the forecast, the weak surface through over the western
Yucatan Peninsula will produce heavy rain over the peninsula and
northern Central America through today as it moves NW into the
SW Gulf of Mexico today. It will then move slowly N or NE over
the western or central Gulf of Mexico Mon and Tue. Upper-level
winds are only expected to be marginally conducive for tropical
cyclone formation, but some slow development is possible while
the system moves across the Gulf of Mexico through the middle of
the week. Elsewhere, a stationary front over the northeast Gulf
will gradually dissipate today, while weak high pressure
dominates much of the remainder of the basin.

CARIBBEAN SEA...

See the Tropical Waves section above for details on a tropical
wave in the central Caribbean.

Scattered moderate showers and tstorms are prevalent north of
18N between 73W-84W, between Haiti and the area south of central
and western Cuba. Farther south, showers and tstorms are more
isolated in coverage. This activity is being enhanced by weak
upper-level diffluence, as a result of an upper-level trough
just north of that area. A surface trough extending from the
west coast of the Yucatan Peninsula to Guatemala is inducing
numerous strong convection over Guatemala and southern Belize
from 15N-18N between 87.5W-92W. The latest ASCAT pass shows
fresh E winds covering the eastern half of the Caribbean, east
of the tropical wave along 74W. Gentle winds cover the western
half of the basin, except for moderate speeds in the Gulf of
Honduras. Seas are 2 to 4 ft in the NW Caribbean and 4 to 6 ft
elsewhere, highest in the southern half of the basin south of
15N.

For the forecast, Hurricane Larry will remain well N and E of
the area into early this week, then move N and away from the
area. Associated swell will move west of 55W early today,
reaching the Leeward Islands and NE Caribbean passages by early
Mon, then gradually subside through mid week as Larry moves
farther north of the region. Elsewhere, gentle to moderate trade
winds will persist, pulsing to fresh winds off Colombia mainly
at night.

ATLANTIC OCEAN...

The latest set of ASCAT passes from early Saturday evening
around 04/2300 UTC show that the area of winds greater than 20
kt associated with the circulation of Hurricane Larry covers a
large area from 13.5N to 24N between 42W and 53.5W. NOAA buoy
41040 near 14.5N 53.3W is reporting seas of 9 ft, mostly in
swell from Larry. For more details on major Hurricane Larry,
please see the Special Features section above.

Elsewhere, a weak stationary front extends from 31N73W to Cape
Canaveral Florida. An upper-level low is near 23N66W. As a
result of both features, scattered moderate showers and tstorms
are noted over portions of the western Atlantic west of 64W,
with greatest concentration of tstorms near the southeast
Bahamas. Moderate wind speeds cover much of the area north of
27N and west of 65W, where seas are 4 to 5 ft. A surface ridge
axis extends from a 1019 mb high pressure near 28N38W to a 1020
mb high pressure near 30N50W to 25N70W to the Florida Straits.
As a result, light to gentle winds are found from 22N-27N, west
of 60W, where seas are 2 to 4 ft. ASCAT shows fresh NE winds
over the E Atlantic east of 30W from 13N-22N.

For the forecast, the west Atlantic stationary front will weaken
today and dissipate early Mon. Hurricane Larry will move to near
20.5N 51W this evening, near 23.0N 54.5W Mon evening, 26N 57.5W
Tue evening and be near 29.5N 60.5W Wed evening. Rough seas in
the form of large swell generated by Hurricane Larry are
expected to propagate across the waters northeast of the Leeward
Islands today, then spread west of 65W through the early part of
the week.

$$
Hagen
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